Stabilization of homo-or copolymeric polyolefins with diacyl dihydrazides

ABSTRACT

A process for stabilising homo- or copolymeric polyolefins, especially polypropylene, with certain symmetrical or asymmetrical diacyl dihydrazides is disclosed, said diacyl dihydrazides possessing good colour properties, and said process being particularly advantageous with respect to thermooxidative decomposition in the presence of transition metals.

United States Patent [191 Miiller et al.

1*July 15, 1975 STABILIZATION OF HOMO-OR COPOLYMERIC POLYOLEFINS WITH DIACYL DIHYDRAZIDES [75] Inventors: Helmut Miiller, Benningen, Basel- Land', Siegfrid Rosenberger, Riehen, Basel-Stadt; Heimo Brunetti, Reinach, Basel-Land, all of Switzerland [73] Assignee: Ciba-Geigy Corporation, Ardsley,

[ Notice: The portion of the term of this patent subsequent to May 22, 1990, has been disclaimed.

[22] Filed: May 11, 1973 [21] Appl. No.: 359,587

Related US. Application Data [63] Continuation of Ser. No. 141,027, May 6, 1971, Pat.

[52]U.S. c1 ..260/45.85 B; 260/4585 s; 260/4590 QB; 260/459 NC; 260/4595 R 51 Int. CI. ..1 C081 45/60 [58] Field0fSearch...260/45.9 NC,45.85 P,45.85 B

Primary ExaminerV. P. I-Ioke Attorney, Agent, or Firm-Karl F. Jorda; Nestor W. Shust; Charles W. Vanecek [57] ABSTRACT A process for stabilising homoor copolymeric polyolefins, especially polypropylene, with certain symmetrical or asymmetrical diacyl dihydrazides is disclosed said diacyl dihydrazides possessing good colour properties, and said process being particularly advantageous with respect to thermooxidative decomposition in the presence of transition metals.

11 Claims, No Drawings STABILIZATION OF HOMO-OR COPOLYMERIC POLYOLEFINS WITH DIACYL D IHYDRAZIDES This application is a continuation application of U.S. Application Ser. No. 141,027, filed on May 6, 1971, now US Pat. No. 3,734,885.

The object of the present invention is a process for stabilising homoor copolymeric polyolefins by the use of diacyldihydrazides.

By virtue of their physical and electrical properties, polyolefins, especially polypropylene, are very suitable as insulation material in electrical engineering, particularly for the sheathing and coating of copper wires, copper cables, and other electrically conducting materials made from copper. Unfortunately, however the stated good properties of polyolefins are spoilt in that the polyolefins undergo, when in contact with transition metals, especially copper and its compounds, an oxidative decomposition catalysed by these metals. Copper additions of below 1%, for example, already lead to a lowering of the oxidation stability of polypropylene by the factor 100.

Already known for the stabilisation of polyolefins against the harmful effect of transition metals are various acylation products from dicarboxylic acids and nitrogen bases, such as, e.g. amides of oxalic acid, especially oxanilides, as well as dihydrazides of various dicarboxylic acids.

All these compounds have certain technical disadvantages. On the one hand, their effectiveness is under no circumstances sufficiently high to completely prevent the damaging effect of the transition metal. On the other hand, the polyolefm becomes discoloured in a harmful manner either at the time these compounds are being worked in or when the polyolefin is exposed to thermooxidative ageing conditions. It is this latter disadvantage in particular which occurs in the case of another known class of effective dicarboxylic acid dihydrazide derivatives, i.e. in the case of bis-arylidenedicarboxylic acid dihydrazides. These do indeed have a satisfactory deactivator-effect, but are already in themselves yellow coloured compounds. None of the types of compounds which have become known combines within itself the technically desired optimum stabilisation effect with colourlessness under working conditions.

Surprisingly, it has now been found that compounds of formula I O O O wherein R and R independently of each other represent alkyl having from 1 to 17 carbon atoms, cyclohexyl, aralkyl which can be substituted by one or two alkyl groups having each from 1 to 4 carbon atoms andlor a hydroxyl group, phenyl, chlorophenyl, dichlorophenyl, phenyl which can be substituted by one or two alkyl groups having each from 1 to 4 carbon atoms and- /or a hydroxyl group, alkylphenyl having from 7 to 14 carbon atoms, alkoxyphenyl having from 7 to 24 carbon atoms or naphthyl, X represents the direct bond, an alkylene radical having from 2 to 8 carbon atoms, a phenylene radical or a naphthylene radical, and n represents 0 or 1, are very suitable for the stabilisation of homoor copolymeric polyolefins, especially with respect to thermooxidative decomposition in the presence of transition metals; and that these compounds at the same time possess good colour properties.

The compounds usable according to the invention are not only excellent stabilisers, which in their effectiveness clearly surpass the above described classes of compounds, but also have the advantage of colourlessness. This renders possible their incorporation into polyolefins without these thereby becoming harmfully discoloured. Furthermore, all the above mentioned previously known compounds have the property of having a discolouring effect in polyolefins under ageing conditions, whilst the compounds usable according to the invention thereby produce no discolouration, which constitutes a great technical advantage with regard to long-duration stabilisation. Moreover, in some cases compounds usable according to the invention afford increased thermostability in polyolefins even in the absence of heavy metals.

R and R, respectively, represent a formula I, e.g. an alkyl group having from 1 to 17 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, iso-heptyl.

octyl, decyl, undecyl, dodecyl, tetradecyl, or heptadecyl; or an alkylphenyl group having from 7 to 14 carbon atoms such as, e.g. phenyl which is substituted by methyl, tert.butyl, or tert. octyl groups; or an alkoxyphenyl group having from 7 to 24 carbon atoms such as, e.g. phenyl which is substituted by methoxy, propoxy, butoxy, hexoxy, octoxy, decyloxy, dodecyloxy, tetradecyloxy or octadecyloxy.

Examples of aralkyl or phenyl radicals represented by R and R, respectively, which radicals can be substituted by one or two alkyl groups having each from 1 to 4 carbon atoms and/or a hydroxyl group are: the 4- hydroxy-2-phenylethyl, 4-hydroxyphenyl, 3-tert.butyl- 4-hydroxy-B-phenylethyl, 3-methyl-4-hydroxyphenyl, 2-hydroxy-3 ,5-di-tert.butyl-phenyl and 3 ,5 -diisopropyl-4-hydroxy-B-phenylethyl radical, more especially, however, the 3,5-di-tert.butyl-4-hydroxy-B- phenylethyl and 3,5-di-tert.butyl-4-hydroxyphenyl radical.

When X in Formula I represents an alkylene radical having from 2 to 8 carbon atoms, this can be, e.g. ethylene, propylene, butylene, pentylene, hexylene, or octylene. X however can also represent a phenylene radical such a the 1,3- or 1,4-phenylene radical, or a naphthylene radical such as the 2,6- or 1,4-naphthylene radical.

Preferred asymmetrical compounds of Formula I are those wherein R and R independently of each other represent alkyl having from 1 to 8 carbon atoms, cyclohexyl, benzyl, 3,5-di-tert.butyl-4-hydroxy-B- phenylethyl, 3,5-di-tert.butyl-4-hydroxyphenyl, phenyl, chlorophenyl, dichlorophenyl, alkylphenyl having 7 to 8 carbon atoms, alkoxyphenyl having 7 or 8 carbon atoms or naphthyl, and X represents the direct bond.

Preferred symmetrical compounds of Formula I are compounds in which R and R are identical and each represents alkyl having from 1 to 12 carbon atoms, cyclohexyl, benzyl, hydroxy-B-phenylethyl or hydroxyphenyl di-substituted by alkyl having from 1 to 4 carbon atoms, phenyl, chlorophenyl, dichlorophenyl, alkylphenyl having from 7 to 12 carbon atoms, alkoxyphenyl having from 7 to 12 carbon atoms or naphthyl, and X represents the direct bond.

In this first preferred group of symmetrical compounds of Formula 1, those which have particularly good stabilisation properties are the compounds in which R and R are identical and each represents alkyl having from 2 to 8 carbon atoms, cyclohexyl, benzyl, 3,5-di-tert.butyl-4-hydroxy-fi-phenylethyl, 3,4-ditert.butyl-4-hydroxyphenyl, phenyl, chlorophenyl, dichlorophenyl, alkylphenyl having 7 to 8 carbon atoms, alkoxyphenyl having 7 to 8 carbon atoms or naphthyl, and X represents the direct bond.

A second preferred group of symmetrical compounds usable according to the invention are the compounds in which R and R are identical and each represents alkyl having from 1 to 12 carbon atoms, cyclohexyl, benzyl, hydroxy-B-phenylethyl or hydroxyphenyl disubstituted by alkyl having from I to 4 carbon atoms, phenyl, chlorophenyl, dichlorophenyl, alkylphenyl having from 7 to 12 carbon atoms, alkoxyphenyl having from 7 to 12 carbon atoms or naphthyl, and X represents an alkylene radical having from 2 to 8 carbon atoms.

In this second preferred group of symmetrical compounds of Formula I, those which have particularly good stabilisation properties are the compounds in which R and R are identical and each represents alkyl having from 1 to 4 carbon atoms, phenyl, chlorophenyl, dichlorophenyl, alkylphenyl having 7 or 8 carbon atoms, alkoxyphenyl having 7 or 8 carbon atoms or naphthyl, and X represents an alkylene radical having from 2 to 8 carbon atoms.

A third preferred group of symmetrical compounds of Formula I are the compounds of which R and R are identical and each represents alkyl having from 2 to 17 carbon atoms, cyclohexyl, benzyl, hydroxy-B- phenylethyl or hydroxyphenyl di-substituted by alkyl having from 1 to 4 carbon atoms, phenyl, chlorophenyl, dichlorophenyl, alkylphenyl having from 7 to 14 carbon atoms, alkoxyphenyl having from 7 to 18 carbon atoms or naphthyl, and X represents phenylene or naphthylene.

In this third preferred group of symmetrical compounds of Formula I, those which have particularly good stabilisation properties are the compounds in which R and R are identical and each represents alkyl having from 2 to 17 carbon atoms, cyclohexyl, alkylphenyl having from 10 to 14 carbon atoms or alkoxyphenyl having from 10 to 14 carbon atoms, and X represents phenylene or naphthylene.

Especially good stabilisation properties are possessed, for example, by the following compounds of Formula I:

N,N'-di-propionyloxalic acid dihydrazide,

N,N-di-butyroyloxalic acid dihydrazide,

N,N'-di-pelargonyloxalic acid dihydrazide,

N,N'-di-cyclohexanoyloxalic acid dihydrazide,

N,N'-di-phenylacetyloxalic acid dihydrazide,

N,N'-di-benzoyloxalic acid dihydrazide,

N,N'-di-a-naphthoyloxalic acid dihydrazide,

N,N'-di-o-toluoyloxalic acid dihydrazide,

N,N-di-p-methoxybenzoyloxalic acid dihydrazide,

N,N'-di-caproyloxalic acid dihydrazide,

N,N'-di-capryloyloxalic acid dihydrazide,

N,N'-di-acetylsuccinic acid dihydrazide,

N,N-di-acetyladipic acid dihydrazide,

N,N'-di-propionyladipic acid dihydrazide,

N,N'-di-acetylsebacic acid dihydrazide,

N,N-di-benzoylsebacic acid dihydrazide,

N,N'-di-B-naphthoylsebacic acid dihydrazide,

N,N'-di-propiony]terephthalic acid dihydrazide,

4 N,N'-di-pelargonylterephthalic acid dihydrazide, N,N-di-2-ethylhexanoylterephthalic acid dihydrazide,

N,N-di-lauroylterephthalic acid dihydrazide,

N,N'-di-stearoylterephthalic acid dihydrazide,

N,N'-di-p-(tert.octyl)-benzoylterephthalic acid dihydrazide,

N,N-di-p-(octoxy)-benzoylterephthalic acid dihydrazide,

N,N'-ditridecanoylterephthalic acid dihydrazide,

N,N-di-palmitoylterephthalic acid dihydrazide,

N,N-di-valeroylterephthalic acid dihydrazide,

N,N'-di-butyroylisophthalic acid dihydrazide,

N,N-di-pelargonylisophthalic acid dihydrazide,

N,N-di-cyclohexanoylisophthalic acid dihydrazide,

N,N-di-2-chlorobenzoyloxalic acid dihydrazide,

N,N-bis-2,4-dichlorobenzoylsebacic acid dihydrazide,

N-benzoyl-N'-butyroyloxalic acid dihydrazide,

N-benzoyl-N-pelargonyloxalic acid dihydrazide,

N,N-bis-(3,5-di-tert.butyl-4-hydroxybenzoyl)-oxalic acid dihydrazide, and

N,N-bis-[ 3 3 ,5-di-tert.butyl-4-hydroxyphenyl propionyl]-adipic acid dihydrazide.

Polyolefins are protected by compounds of Formula I against decomposition, preferably a-olefin-polymers such as polypropylene, optionally cross-linked polyethylene, polyisobutylene, polymethylbutene-l polymethylpentene-l polybutene-l, polyisoprene, polybutadiene; copolymers of monomers on which the mentioned homopolymers are based, such as ethylene-propylenecopolymers, propylene-butenel -copolymers, propylene-isobutylene-copolymers, styrene-butadienecopolymers, as well as terpolymers of ethylene and propylene with a diene such as, e.g. hexadiene, dicyclo pentadiene or ethylidenenorbornene; mixtures of the above mentioned homopolymers such as, e.g. mixtures of polypropylene and polyethylene, polypropylene and poly-butene-l, polypropylene and polyisobutylene. Thereby preferred are polypropylene as well as its mixtures, and the copolymers containing propylene units.

The compounds of Formula I are usually incorporated into the substrates in a concentration of from 0.01 to 5 per cent by weight, calculated on the material to be stabilised.

Preferably, an amount of from 0.05 to 1.5 per cent by weight, especially preferred from 0.1 to 0.8 per cent by weight, of the compounds, calculated on the material to be stabilised, is incorporated into this material.

The incorporation can be effected after polymerisation, e.g. by the mixing in of at least one of the compounds of formula I and, optionally, further additives into the melt by methods common in practice, before or during shaping; or by application of the dissolved or dispersed compounds to the polymer, optionally with subsequent evaporation of the solvent.

In the case of cross-linked polyethylene, the compounds are added before cross-linking.

Further additives together with which the stabilisers usable according to the invention can be used are as follows:

1. Antioxidants of the aminoand hydroxyaryl series. To be mentioned in the case of the latter are the sterically hindered phenol compounds, e.g.

2,2-thiobis-(4-methyl-6-tert.butylphenol),

4,4-thiobis-( 3-methyl-6-tert.butylphenol 2,2methylene'-bis-'(4-methyl-6-tert.butylphenol),

2,2-methylene-bis-(4 ethyl-6-tert.butylphenol), 4,4'-methylene-bis-(2-methyl-6-tert.butylphenol),

4 ,4 -butylidine-bis-( 3-methyl-6-tert.butylphenol 2,2'-methylene-bis-[4-methyl-6-(a-methylcyclohexyl)-phenol],

2,6-di-(2-hydroxy-3-tert.butyl-S-methylbenzyl)-4- methylphenol,

2,6-di-tert.butyl-4-methylphenol,

1 ,l ,3-tris-2-methyl-(4-hydroxy-5-tert.butylphenyl)- butane,

l ,3 ,5-trimethyl-2,4,6-tri-( 3 ,5-di-tert.butyl-4- hydroxy-benzyl)-benzene,

esters of B-4-hydroxy-3,5-di-tert.butylphenylpropionic acid with monoand polyvalent alcohols such as methanol, ethanol, octadecanol, hexanediol, nonanediol, thiodiethyleneglycol, trimethylolethane, or pentaerythrite,

2,4-bis-octylmercapto-6-(4-hydroxy-3,S-ditert.butyl-anilino)-s-triazine,

2,4-bis-(4-hydroxy-3,5-di-tert.butylphenoxy)-6- octylmercapto-s-triazine,

l 1 -bis-( 4-hydroxy-Z-methyl-5-tert.butylphenyl )-3- dodecyl-mercaptobutane,

4-hydroxy-3,5-di-tert.butylbenzyhphosphonic acid ester, such as dimethyl, diethyl, or dioctadecyl ester,

(3 -methyl-4-hydroxy-5 -tert.butylbenzyl )-malonic acid dioctadecyl ester,

s-(3 ,5-dimethyl-4-hydroxyphenyl)-thioglycolic acid octadecyl ester,

esters of bis-(3,5-di-tert.butyl-4-hydroxybenzyl)- malonic acid such as didodecyl ester, dioctadecyl ester, 2-dodecyl-mercaptoethyl ester.

Of the aminoaryl derivatives are to be mentioned aniline and naphthylamine derivatives, as well as their heterocyclic derivatives, e.g.

phenyl- 1 -naphthylamine,

phenyl-Z-naphthylamine,

N,N -diphenyl-p-phenylenediamine,

N ,N '-di-2-naphthyl-p-phenylenediamine,

N,N'-di-sec.butyl-p-phenylenediamine,

6-ethoxy-2,2,4-trirnethyl-l ,2-dihydroquinoline,

6-dodecyl-2,2,4-trimethyl-l ,2-dihydroquinoline,

monoand dioctyliminodibenzyl,

polymerised 2,2,4-trimethyl-l ,2-dihydroquinoline,

whereby though with the combined use of compounds of Formula I with the above mentioned amine compounds the stabilised polymer no longer possesses, on account of the discolouration tendency of the said amine compounds, such good colour properties.

2. UV-absorbers and protective agents against light rays, such as l ,3-bis-( 2'-hydroxy-4'-octoxybenzoyl)-benzene,

l,3-bis-( 2'-hydroxy-4'-dodecyloxybenzoyl)-benzene.

e. Aryl esters of optionally substituted benzoic acids,

such as, e.g. phenylsalicylate, octylphenylsalicyclate, benzoyl-resorcin, dibenzoylresorcin, 3,5-ditert.butyl-4-hydroxybenzoic acid-2,4-ditert.butylphenyl ester or -octadecyl ester.

f. Acrylates, e.g. a-cyano-B,B-diphenylacrylic acid ethyl ester or isooctyl ester, a-carbomethoxycinnamic acid methyl ester, a-cyano-B-methyl-pmethoxycinnamic acid methyl or butyl ester, N-( B- carbomethoxyvinyl)-2-methyl-indoline.

g. Nickel compounds, e.g. nickel complexes of 2,2-

thiobis-(4-tert.octylphenol), such as the l:land l:2-complex, optionally with other ligands such as n-butylamine, nickel complexes of bis-(4-tert.octylphenyl)-sulphone, such as the 2:1-complex, optionally with other ligands such as 2-ethylcapronic acid, nickel dibutyldithiocarbamate, nickel salts of 4-hydroxy-3,5-di-tert.butylbenzylphosphonic acid monoalkyl esters, such as methyl, ethyl, or butyl ester, the nickel complex of 2-hydroxy-4-methylphenyl-undecyl ketone oxime.

h. Oxalic acid diamides, e.g. 4,4dioctyloxyoxanilide, 2,2 '-di-octyloxy-5 ,5 '-ditert.butyloxanilide, 2,2 -di-dodecyloxy-5 ,5 '-ditert,butyloxanilide.

3. Phosphites, such as triphenylphosphite,

diphenylalkylphosphites,

phenyldialkylphosphites,

trinonylphenylphosphite,

trilaurylphosphite,

trioctadecylphosphite,

3 ,9-di-isodecyloxy-2,4,8, l O-tetraoxa-3 ,9-

diphosphaspiro-(5,5)-undecane,

tri-(4-hydroxy-3,5-di-tert.butylphenyl)-phosphite.

4. Nucleation agents, such as 4-tert.butylbenzoic acid, adipic acid, diphenylacetic acid.

5. Peroxide-decomposing compounds, such as esters of B-thiodipropionic acid, e.g. lauryl, stearyl,

myrystyl or tridecyl ester.

Salts of 2-mercaptobenzimidazoles, e.g. the zinc salt,

diphenylthiourea.

6. Other additives such as softeners, antistatica, fireproofing agents, pigments, soot, asbestos, glass fibres, kaolin, talcum.

In the case of using the stabilisers according to the invention in combination with phenolic antioxidants, particularly good stabilising effects are obtained when at the same time are used peroxide-decomposing compounds such as higher alkyl esters of thiopropionic acid, since these peroxide-decomposing compounds exhibit synergism not only, as is known, with the phenolic antioxidants but additionally with the stabilisers of Formula l.

The production of the symmetrical compounds usable according to the invention can be effected, in particular, by two reaction sequences known per se:

a. Double acylation of a dicarboxylic acid hydrazide with the usual acylation agents, e.g. monocarboxylic acid chlorides or monocarboxylic acid anll); drides; or

b. Reaction of two moles of a monocarboxylic acid hydrazide with one mole of a reactive derivative of a dicarboxylic acid, e. g. dicarboxylic acid diester or a dicarboxylic acid dichloride. The production of asymmetrical compounds of Formula I is advantageously carried out by reacting in a 8 dipropionyladipic acid dihydrazide (stabiliser 2), M.P. 260265C (recrystallisation from dimethylformamide).

If, in the present Example, the acetic anhydride is re- ()mgcocl manner known per se, a dicarboxylic acid ester chloplaced by phenylacetic acid chloride, then is obtained, ride with a monocarboxylic acid hydrazide to obtain with otherwise an analogous procedure, N,N'- the corresponding dicarboxylic acid monoester acyl hydiphenylacetyladipic acid dihydrazide, M.P. drazide, reacting the latter with hydrazine to form the 310316C (stabliser 3) (recrystallisation from dimono-acylated dicarboxylic acid di-hydrazide and submethylformamidclsequently N-acylating the reaction rod t ith a If the acetic anhydride is replaced by stearic acid monocarboxylic acid chloride or a monocarboxylic Chloride, then is Obtained, with an analogous P acid anhydride. dure, N,N'-di-stearoyladipic acid dihydrazide (stabi- The polyolefins stabilised by the addition of the comliser 4), pounds usable according to the invention are especially If h acetic n y r i r p y Ot0lui0 ac suitable as coating material for copper wires and cachloride or p-methoxybenzoyl chloride, then is obbles, but also for other types of metal coating, as well With Otherwise the Same Procedure, as for the production of shaped articles such as films, toluoyladipic acid dihydrazide (stabiliser 5) with softthreads, sheets, tubes, injection-moulded articles, etc.. ening point above 200C, or N,N-di-p- They can also be mixed with copper or with coppermethoxybenzoyladipic acid dihydrazide (stabiliser 6) containing pigments. with softening point above 210C. The invention 18 further illustrated in the following EXAMPLE 2 examples.

EXAMPLE 1 CONHNHCOCHG Cl-l CONHNl-1CO(CH CONl-1NHCOCl-l CONHNHCOCHs An amount of 17.4 g (0.1 mol) of adipic acid dihydrazide is suspended in 100 ml of dimethylacetamide. An amount of g of oxalic id dihy- The suspension is heated to 100C, and to it are added, drazide is Suspended 120 ml of dimethylacetamide; with stirring, 20.4 g (0.2 mol) of acetic anhydride, the t0 the Suspension are then added dropwise at addition being made at such a rate that the charge is with stirring, g of acetyl 'id Th maintained at 100C purely by the heat f reaction, reaction mixture is stirred at room temperature for a without additional heating. The cheese-like white susfurther ha1fh0u1',the P y White precipitate isolate, pension is heated for a further 2 hours to 100C, then and well washed with water. For purification, the prodcooled, filtered off under suction, and the residue uct is washed with acetonitrile. washed with alcohol. Thus obtained is N,N'-diacetyloxalic acid bishydra- The thus obtained N,N'-di-acetyladipic acid dihydrazide (stabiliser 7), MP. 285287C. zide (stabiliser l) melts, after drying, at 256259C, in thfi Present E pl the yl hl d s 1'8- and can be recrystallised from dimethylacetamide. placed by one of the acid chlorides given in the follow- If, in the above Example, the acetic anhydride is reing Table 1, then are obtained, with otherwise an analoplaced by propionic acid anhydride, then is obtained, gous procedure, the corresponding N,N'-diacyloxa1ic with otherwise an analogous procedure, N,N'- acid dihydrazides having the following melting points:

Table 1 Acid chloride MP. of the obtained Recrystallised Stabi R CO Cl diacyloxalic acidbisfrom liser hydrazide of the formula RCONHNH- COCONHNHCOR C H COCl 266 8 nC;,l'l COCl ca. 276 with ethylene glycol decomposition monomethyl ether 9 nC H -,COC1 250 10 nC H,,CH-COC1 215 218 dimethyltormamide 1 l z s nC H ;,COC1 212 215 12 C6H5-COC1 about 260 with 13 decomposition ll CCCI ca.280 ethylene glycol 14 monomethyl ether 350 dimethylacetamide l5 Table l-Co-ntinued Acid chloride M.P. of the obtained Recrystallised Stabi- R CO C] diacyloxalic acidbisfrom liser hydrazide of the formula RCONHNH- COCONHNHCOR (10C). 295 298 ethylene glycol 16 monomethyl ether Q C H COCI softening point EXAMPLE 3 An amount of 14.6 g (0.1 mol) of succinic acid dihy- CONHNHCOCH;;

l CONHNHCO-CH;

An amount of 11.8 g (0.1 mol) of oxalic acid dihydrazide is suspended in 120 ml of dimethylacetamide; to the suspension are then added, with stirring, 25.5 g (0.25 mol) of acetic anhydride, and the whole is heated for 2 hours to 50C.

The white crystalline precipitate is isolated, washed first with water and then with ethanol, and dried.

Thus obtained is a product, M.P. 284286C, identical to the N,N'-diacetyloxalic acid dihydrazide described in Example 2 (stabiliser 7-).

EXAMPLE 4 CONHNHCOCH,

CONHNHCOCH 14.6 g (0.1 mol) of oxalic acid diethyl ester and 16.3 g (0.22 mol) of acethydrazide are refluxed in 130 ml of dimethylacetamide for 5 hours. After cooling, the white crystalline precipitate is isolated, washed with water and afterwards with alcohol, and dried.

Thus obtained is a product, M.P. 284287C, identical to the N,N-diacetyloxalic acid dihydrazide described in Example 2 (stabiliser 7).

EXAMPLE 5 NHNHCOCHQ o NHNHCOCH EXAMPLE 6 CH CONHNHCOCH CH CONHNHCOCH drazide is suspended in 130 ml of dimethylacetamide; to the suspension are then added, with stirring, 20.4 g (0.2 mol) of acetic anhydride. The reaction is exothermic. The reaction mixture heats up from 20 to ca. 40C, and a thick crystal mass is formed. After a further hour of reaction time at 50C, the white crystalline product is isolated from the mother liquor, and washed with ethylene glycol monomethyl ether. The thus obtained N,N'-diacetylsuccinic acid dihydrazide (stabiliser 19) melts at 254255C.

EXAMPLE 7 An amount of 26.4 g (0.1 mol) of p-n-octoxybenzohydrazide is suspended in 200 ml of dimethylacetamide, to the suspension are then added within 20 minutes, with stirring, 10.2 g (0.05 mol) of terephthalic acid dichloride. The reaction mixture thereby heats up to ca. 35C. The charge is'thereupon stirred for minutes at 65C, then cooled, filtered off under suction, and the suction-filter residue recrystallised from dimethylformamide.

The thus obtained N,N-di-p-n-octoxybenzoylterephthalic acid dihydrazide (stabiliser 20) melts at 3l0-3l6C.

EXAMPLE 8 (C,7H35CONHNHCO)2(CH2)2 An amount of 14.6 g (0.1 mol) of succinic acid hydrazide is suspended in 200 ml of dimethylacetamide; to the suspension are then added, with stirring, 66.7 g (0.22 mol) of stearic acid chloride. The temperature of the reaction mixture thereby rises to about 45C, and the suspension becomes voluminous. The charge is maintained for a further 3 hours at 60C, then cooled, and the microcrystalline precipitate isolated. For purification, the product is boiled with 500 ml of ethanol. After isolation and drying is obtained a white powder of N,N'-di-stearoylsuccinic acid dihydrazide (stabiliser 21), M.P. 248252C.

EXAMPLE 9 An amount of 19.4 g (0.1 mol) of isophthalic acid dihydrazide is suspended in 200 ml of dimethylacetamide; to the suspension are added within 20 minutes, with stirring, 16.4 g (0.21 mol) of acetyl chloride. The temperature of the reaction mixture thereby rises to ca. 40C, and a practically clear solution is formed. The charge is stirred for a further 3 hours at room temperature, and subsequently poured into 1000 ml of water, whereby the reaction product is obtained as a white pulverulent precipitate. For purification, the thus obtained N,N-diacetylisophthalic acid dihydrazide (stabiliser 22) is recrystallised from ethanol, M.P. 264C.

If, in the present Example, the acetyl chloride is replaced by pelargonic acid chloride, then is obtained, with otherwise the same procedure, N,N- dipelargonylisophthalic acid dihydrazide (stabiliser 23), MP. 218C.

If, in the present Example, the acetyl chloride is replaced by benzoyl chloride, then is obtained N,N'- dibenzoylisophthalic acid dihydrazide (stabiliser 24), M.P. 297-299C.

EXAMPLE l CH CONHNHCO(CH CONHNHCOCH If the acetyl chloride is replaced by an equivalent 12 Table 2 Continued Acid chloride Melting point of the obtained Slabiliser (R-COCI) diucylsebacic acid dihydrazide No.

ONl'iNIlCOC I-l (n) (ZONI-lNllCOC I-i (n) An amount of 19.4 g (0.1 mol) of terephthalic acid dihydrazide is suspended in 200 ml of dimethylacetamide; to the suspension are then added, within 20 minutes, 37.0 g (0.21 mol) of pelargonic acid chloride. The temperature of the reaction mixture thereby rises to ca. 40C, and a voluminous-crystalline suspension is formed. The charge is stirred for a further 3 hours at room temperature, and subsequently poured into 100 ml of water. The white pulverulent precipitate is isolated, dried, and recrystallised from a little dimethylformamide. The thus obtained N,N'-dipelargonylterephthalic acid dihydrazide (stabiliser 30) has a melting point of 276C.

If, in the present Example, the pelargonic acid chloride is replaced by one of the acid chlorides shown in the following Table 3, the procedure being otherwise analogous, then are obtained the corresponding N,N'-diacrylterephthalic acid dihydrazides having the given MP. A

Table 3 Acid chloride Diacylterephthalic acid Recrystallised Stabiliser RCOCl dihydrazide from No. l\\"-0Z: "'?J=' 0t15:43:10:-

i formamide 32 formamide amount of one of the acid chlorides listed in the following Table 2, then are obtained the corresponding N,N'- diacylsebacic acid dihydrazides having the given melting point.

Table 2 Acid chloride Melting point of the obtained Stabiliser (R-COCl) diacylsebacic acid dihydrazide No.

of the formula EXAMPLE 12 The diacyl dicarboxyliev acid dihydrazides listed in the following Table 4 are prepared according to the procedure described in theExamples mentioned in column 4 of said Table4 O O O Table 4 R X Melting Prepared Stabiliser point according to No. Example cH,),- 250C 1 3s an m 'J/ -(CH2)4 228C 1 36 H C O i 258C 7 37 (:lgHfi (EH3 I a C H -CH (".CH C-CH 120C 10 38 CH CH l l H C O CCH CCH 184C 10 39 direct bond 250C 2 40 I// 4- direct bond 272C 2 41 C]. m Act-Mr 246C 10 42 c 1 -(CH-,),. 266C 10 43 EXAMPLE 13 stirred for 3 hours at 6070C, then 500 ml of ice a. 13.6 g (0.1 mol) of benzanhydride are dissolved in 70 m1 of dimethylacetamide. The resultant solution is cooled to 0C and then 10.0 g (0.1 mol) of triethylamine are added thereto. Subsequently 15.0 g (0.1 1 mols) of oxalic acid monoethylester chloride are added dropwise. The mixture is stirred at C for 2 hours, then cooled and admixed with 500 ml of water. After filtering and drying there is obtained N-benzoyloxalic acid monoethylester hydrazide, M.P. 132C.

b. l 1.8 g (0.05 mols) of N-benzoyloxalic acid monoethylester hydrazide are dissolved in 100 ml of alcohol and 5.0 g (0.1 mol) of hydrazine hydrate are added thereto. The N-benzoyloxalic acid dihydrazide formed is sucked off, washed with alcohol and dried, MP. 226C.

0. 11.1 g (0.05 mols) of N-benzoyloxalic acid dihydrazide are suspended in 250 ml of dimethylacetamide and dropwise admixed, while stirring, with 5.8 g (0.055 mols) of butyric acid chloride. The reaction mixture is water are added and filtering under suction is carried out at 5l0C. The resultant product is recrystallised from methylcellosolve. There is obtained N-benzoyl- N-butyroyloxalic acid dihydrazide (stabiliser 44), MP. 254c.

EXAMPLE 14 68 g of 3-(3,5-di-tert.butyl-4-hydroxyphenyl)- propionic acid hydrazide are suspended in 300 ml of dimethylacetamide and then admixed, while stirring, within 20 minutes with 21.3 g of adipic acid dichloride. The mixture is then stirred for another hour at 70C, admixed with 1000 ml of water and filtered. The reaction product can also be purified by dissolving it in methanol, followed by carefully precipitation with water. The bis-[3-(3,5-di-tert.butyl-4-hydroxyphenyl)- propionyl]-adipic acid dihydrazide thus obtained (stabiliser 45) melts at 240C.

If, in the above Example, the adipic acid dichloride is replaced by an equivalent amount of one of the dicarboxylic acid dichlorides given in the following Table 5, the procedure being otherwise the same, then the corresponding bis-[ 3-( 3 ,5 -di-tert.butyl-4-hydroxyphenyl propionyll-dicarboxylic acid dihydrazides are obtained, the melting points of which are indicated in column 3 of said Table.

23 g (0.1 mol) of sebacic acid dihydrazide are suspended in 200 ml of dimethylacetamide. While stirring, 53.6 g (0.2 mols) of 3,5-di-tert.butyl-4-hydroxybenzoyl chloride are added in portions. The mixture is then heated to 80C during 2 hours, cooled and poured into 1 liter of ice water. The solid which precipitates is filtered off and recrystallised from dimethylacetamide. There is obtained bis-(3,5-di-tert.butyl-4-hydroxybenzoy1)-sebacic acid dihydrazide (Stabiliser 48), M.P. 285C Table 6 Stabiliser No. Chemical designation 50 oxanilide 51 oxalic acid dihydrazide 52 carbohydrazide 53 malonic acid dihydrazide 54 adipic acid dihydrazide 55 terephthalic acid dihydrazide 56 N,N'diphenylsuccinic acid dihydrazide 57 N,N-diphenylsebacic acid dihydrazide EXAMPLE 16 a. Preparation of the test samples. 100 parts of polypropylene (melt index 3.2 g/10 min., 230C/216O g) are intensively mixed together in a shaking apparatus, for 10 minutes, with 0.1 parts of B-(3,5-di-t.buty1-4-hydroxyphenyl)-propionic acid octadecyl ester, 0.3 parts of dilaurylthiodipropionate and 0.5 parts of one of the additives listed in the following Table 7.

The obtained mixture is kneaded in a Brabender Plastograph at 200C for 10 minutes; to the mixture is then added 1.0 per cent by weight of powdered copper (electrolytically produced, Merck), and the whole intensively mixed at the same temperature for a further 2 minutes. The thus produced mass is subsequently pressed in a platen press at 260C platen temperature to form 1 mm thick plates, from which are then stamped strips 1 cm wide and 17 cm in length.

The heat-stabilised test samples required for comparison purposes, without or with copper addition but without metal-deactivator, are prepared in an analogous manner.

b. Testing The testing for metaleffectiveness of the Qoa deactivators added to the copper-containing test strips is carried out by heat ageing in an air-circulation furnace at 149C, and the results are compared with results obtained on test strips not containing copper. For this purpose are used in each case 3 test strips of each formu1ation.'The commencing, easily visible decomposition of the test strip is taken as being the end point for each test.

The preservation factor given in the 4th column of Table 7 is defined as follows:

days until decomposition, with copper preservnmn factor days until decomposition, without copper x Table 7 Stabiliser Days until decomposition Preservation 45 No. without Cu with Cu factor without additive 18-27 1 1 1 26 21 81 2 25 22 88 8 34 18 53 9 29 27 93 10 27 26 96 50 13 16 19 105 14 29 29 100 15 29 23 79 16 24 14 58 19 26 65 23 24 15 63 28 23 18 78 3O 27 24 89 31 29 22 76 33 18 18 100 40 21 19 91 41 25 21 84 42 26 18 69 43 23 15 6O 44 25 24 49 23 23 Comparison products 50 18 1 6 51 24 6 25 54 18 2 1 1 55 25 2 8 65 56 21 1 5 57 25 14 56 EXAMPLE 17 a. Preparation of the test samples.

100 parts of polypropylene (melt index 3.2 g/ 10 min., 230C/2160 g) are intensively mixed together, in a shaking apparatus, for 10 minutes, with 0.1 parts of B-(3,5-di-t.butyl-4-hydroxyphenyl)-propionic acid octadecyl ester, 0.3 parts of dilaurylthiodipropionate and 0.5 parts of an additive listed in the following Table 8.

The obtained mixture is kneaded in a Brabender Plastograph at 200C for 10 minutes, and to the mixture is then added 1.0 per cent by weight of powdered copper (electrolytically produced, Merck), and the whole intensively mixed at the same temperature for a further 2 minutes. The thus obtained mass is subsequently pressed in a platen press at 260C platentemperature to form 1 mm thick plates, from which are stamped, with the aid of a stamping tool, strips having a width of 1 cm and a length of 17 cm.

The heat-stabilised test samples required for comparison purposes, without copper addition or with copper addition, but without metal-deactivator, are prepared in an analogous manner.

b. Testing The testing for effectiveness of the metaldeactivators added to the copper-containing test strips is carried out by heat ageing in an air-circulation furnace at 135C, and the results are then compared with results obtained from test strips not containing copper. The commencing, easily visible decomposition of the test strip is taken as being the end point for each test.

The preservation factor shown in column 4 of Table 8 is defined as follows:

days until decomposition, with copper eservauon factor days until decomposition, without copper Table 8 Stabiliser No,

Days until decomposition Preservation without Cu with Cu factor without additive H 1 1 83 100 100 EXAMPLE 18 The test samples without copper addition described in Examples 16 and 17 were, moreover, tested with respect to their colour stability, as follows:

a. After incorporation (Table 9, Column 2).

b. After heat ageing at 149C (Table 9, Column 3).

An empirical colour scale was used for Table 9, whereby 5 denotes colourlessness, 4 a just perceptible, faint discolouration, and 3, 2, 1, 1 denote successively more severe discolouration.

Comparison products:

Colour rating according to Scale l-5 Stabiliser after incafter heatboiling H O No. orporation ageing 1 week EXAMPLE 19 Parts of polypropylene (melt index 3.2 g/10 min., 230C/2160 g) are intensively mixed for 10 minutes in a shaking apparatus with the additives listed in Table 10, in the given concentrations.

' The obtained mixture is kneaded in a Brabender Plastograph at 200C for 10 minutes; to the mixture is then added 1.0 per cent by weight of powdered copper (electrolytically produced, Merck), and the whole intensively mixed at the same temperature for-a further 2 minutes. The thus obtained mass is subsequently pressed in a platen press at 260C platen-temperature to form 1 mm thick plates, from which are stamped, by means of a stamping tool, strips having a width of 1 cm and a length of 17 cm.

The fully stabilised test samples without copperaddition required for comparision purposes are prepared in an analogous manner.

The testing of the dependence of the effect of the stabilisers on the further additives is carried out by heat ageing in an air-circulation furnace at 149C. For results see Table 10, Column 4. The furnace-ageing times for the test samples without copper addition, required for comparison, are given in Table 10, Column 3.

19 Table Furnace ageing times in days Additives at 149C 7 and until commencing decomposition concentration without copper with copper- Mixture (P. parts) addition addition 0,5 P. Stabiliser l 1 0,2 F. Additive A 8 0,5 P. Stabiliser l3 2 0,2 F. Additive B 10 0,5 P. Stabiliser 3 0,1 F. Additive C 29 15 0,3 F. Stabiliser 1 4 0,3 P. Additive D 17 9 0,4 P. Stabiliser l3 5 0,1 F. Additive E 15 10 0,5 P. Stabiliser 30 0,05 P. Additive E 6 0,15 P. Additive D 28 23 0,4 P. Stabiliser l 0,1 P. Additive B 7 0,3 P. Additive D 32 26 0,5 P. Stabiliser 13 0,1 P. Additive C 8 0,3 F. Additive D 34 0,5 P. Stabiliser l 0,1 P. Additive A 9 0,3 P. Additive F 16 12 E: 3-(3,5-di-tcrt.-butyl-4-hydroxyphcnyl)-propionic acid tetraestcr of pentaerythrite,

F: tris-(n0nylphenyl)-phosphitc.

EXAMPLE 20 100 Parts of polypropylene (melt index 3.2 g/ 10 min., 230C/2160 g) are intensively mixed for 10 minutes, in a shaking apparatus, with the additives listed in Table 11, in the given concentrations.

The obtained mixture is kneaded in a Brabender Plastograph at 200C for 10 minutes; to the mixture is then added 0.1 per cent by weight of copper stearate, and the whole thoroughly mixed at the same temperature for a further 2 minutes. The thus obtained mass is subsequently pressed in a platen-press at 260C platentemperature to form,,1 mm thick plates, from which are stamped, with the aid of a stamping tool, strips having a width of 1 cm and a length of 17 cm.

The fully stabilised test samples without the addition of copper stearate, required for comparision purposes, are prepared in an analogous manner.

The testing of the effectiveness of the metal deactivators (stabiliser No. 14) in the test strips containing copper stearate is performed by heat ageing in an air circulation furnace at 149C. For results see Table 1 1, Column 4. The furnace ageing times, required for comparison, for the test samples without addition of copper stearate are given in Table 11, Column 3.

The designation of the additives IS the same as "1 Example 19.

EXAMPLE 21 100 Parts of polypropylene (melt index 3.2 g/10 min., 230C/2l60 g) are intensively mixed, in a shaking apparatus, with 0.1 parts of 3-(3',5'-di-tert.-butyl-4' hydroxyphenyl)-propionic acid octadecyl ester, 0.3 parts of dilaurylthiodipropionate, and an additive listed in the following Table 12, in the given amount.

The obtained mixture is kneaded in a Brabender Plastograph at 200C for 10 minutes; to the mixture is then added 1.0 per cent by weight of powdered copper (electrolytically produced, Merck), and the whole thoroughly mixed for a further 2 minutes. The obtained mass is subsequently pressed in a platen press, at 260C platen-temperature to form 1 mm thick plates, from which arestamped, with the aid of a stamping tool, strips having a width of 1 cm and a length of 17 cm.

The testing with respect to the effectiveness of the metal deactivators added to the test strips, as a function of the concentration, is performed by heat ageing. in an air circulation furnace at 149C. The results are given in Table 12.

Table l l Furnace-ageing times at 149C Days until commencing Additives and decomposition concentration without copper with copper Mixture (P. parts) stearate stearate 0,2 P. Additive A 1 without metal-deactivator 15 l 0,2 P. Additive A 2 0,5 P. Stabiliser No. 14 17 6 0,1 P. Additive D 3 0,5 P. Stabiliser No. 14 34 24 (Given in the table are the dais f add d N mount e Sta 1 iser until decomposition commences) Stabiliser No. 0 parts 0.1 parts 0.2 parts 0.3 parts 0 5 parts 15 EXAMPLE 22 oxide which has been added, cross-linking of the poly- Stabilisation of asbestos-filled polypropylene 100 parts of polypropylene (Carlona, Shell) are intensively mixed together with 65 parts of 2 Chrysotilasbest (Montecatini), 0.5 parts of 3-(3,5- di-tert.butyl-4-hydroxyphenyl)-propionic acid octadecyl ester, 1.5 parts of dilaurylthiodipropionate and 0.83 parts of one of the additives listed in the following Table 13.

The resultant mixture is kneaded in a Brabender Plastograph for 10 minutes and then pressed in a platen press at 260C platen temperature to form 1 mm thick plates, from which are then stamped strips having a width of 1 cm and a length of 17 cm,

The testing for effectiveness of the additives added to the test strips is carried out by heat ageing in an aircirculation furnace at 149C. The easily visible decomposition of the test strip is taken as being the end point for each test, said decomposition being revealed by the chalking of decomposed material.

The results are given in days.

EXAMPLE 23 100 parts of unstabilised high pressure polyethylene powder (Plastylne, Ethylene Plastique, Mazingarbe, France) are intensively mixed together in the dry state with 1.0 part of 1,3-bis-(tert.-butyl-peroxyisopropyl)benzene (Perkadox 14, Oxydo GmbH, Emmerich, Germany) and 0.2 parts of one of the additives listed in the following Table 14. The mixture is then treated in a friction rolling mill at l 10C for 10 minutes until a homogeneous mass is obtained. The thus produced mixture is subsequently pressed in a platen press at 260C platen temperature for minutes to form 1 mm thick plates. Under these conditions due to the permer occurs. From these plates are then stamped, with the aid of a stamping tool, strips of 10 X 140 mm.

The test strips are then suspended on steel hooks and subjected to heat ageing in an air-circulation furnace at 120C. After an induction time which is significant for the additive used, the decomposed material drips off; the results are given in days.

Table 14 Stabiliser Days until dripping No. starts at 120C without additive 6 1 10 4 12 7 10 12 13 15 1 1 31 12 comparison product 50 EXAMPLE 24 parts of unstabilised polypropylene are intensively mixed together in a shaking apparatus with 0.1 parts of B-(2,3-di-tert.-butyl-4-hydroxyphenyl)-propionic acid octadecyl ester, 0.3 parts of dilaurylthiodipropionate and 0.5 parts of stabiliser No. l.

The obtained mixture is introduced into a Brabender Plastograph and kneaded at 200C for 5 minutes and 30 r.p.m. until a homogeneous mass is obtained. Then, within one minute, a mixture of a further 25 parts of polypropylene and 0.1 parts of Co-ll-stearate, Fe-llstearate and Cu-ll-stearate respectively, is added. After completion of the addition, kneading is continued at the same temperature and r.p.m. for 10 minutes, the moment of rotation being continuously measured in the form of plastograms. Since the moment of rotation, melting viscosity and molecular weight are correlated with each other in that, under otherwise constant conditions, increased moment of rotation results in an increased melting viscositiy and therefore in an increased molecular weight of the polymer, decrease of moment of rotation results in a degradation of the polymer.

The plastograms, required for comparison purposes, of test samples without addition of metal salt and without addition of deactivator and the test samples with metal salt addition and without addition of deactivator are prepared in an analogous manner.

The degradation of the polymer during the kneading period of 10 minutes is expressed by the residual moment of rotation at the end of the kneading period, in per cent of the initial moment of rotation (see Table 15, Column The effectiveness of the metaldeactivator results from the comparison of the figures in Column 5 for each metal salt, with and without Stabiliser No. 1.

a. Preparation of the test samples 100 parts of unstabilised polybutylene-l powder are intensively mixed together in a shaking apparatus with 0.1 parts of B-(3,S-di-tert.-butyl-4-hydroxyphenyl)propionic acid octadecyl ester, 0.3 parts of dilauryl-thiodipropionate and 0.5 parts of stabiliser No. l.

The obtained mixture is kneaded in a Brabender Plastograph at 200C for minutes until a homogeneous mass is obtained; to the mixture is then added 1.0 parts of powdered copper (electrolytically produced), and the whole intensively mixed at the same temperature for a further 2 minutes. The thus produced mass is subsequently pressed during 6 minutes in a platen press at 220C platen temperature to form 1 mm thick plates from which are then stamped strips 1 cm wide and 14 cm in length.

The test samples required for comparison purposes without copper addition are prepared in an analogous manner.

b. Testing The testing for effectiveness of the metal-deactivator added to the copper-containing test strips is carried out by heat ageing in an air-circulation furnace at 110C until the first signs of the commencing decomposition of the test samples appear. In each case 3 test strips of each formulation are used, from which the average ageing time is calculated.

The test strips containing stabiliser No. 1 do not show any signs of decomposition at a time at which the unstabilised test strips are completely decomposed.

What we claim is:

1. A homopolymeric or copolymeric polyolefin composition stabilized in the presence or absence of copper with a. 0.01 to 5% by weight of the polyolefin of a diacyl hydrazide having the formula wherein R and R independently of each other represent alkyl having 1 to 17 carbon atoms; cyclohexyl; aralkyl which can be substituted by one or two alkyl groups, each having from l to 4 carbon atoms and/or a hydroxyl group; phenyl; chlorophenyl; dichlorophenyl; phenyl which is substituted by one or two alkyl groups each having from 1 to 4 carbon atoms and/or a hydroxyl group; alkylphenyl having from 7 to 14 carbon atoms; alkoxyphenyl having from 7 to 24 carbon atoms or naphthyl; X represents the direct bond, an alkylene radical having from 2 to 8 carbon atoms, a phenylene radical or a naphthylene radical, and n represents 0 or 1; and

b. an antioxidant selected from sterically hindered phenol compounds and aminoaryl compounds, and

0. higher alkyl esters of thiodipropionic acid.

2. A composition of claim 1 wherein R and R are independent of each other and represent alkyl having from 1 to 8 carbon atoms, cyclohexyl, benzyl, 3,5-ditert.-butyl-4-hydroxy-B-phenyl-ethyl, 3 ,5-di-tert.-butyl- 4-hydroxyphenyl, phenyl, chlorophenyl, dichlorophenyl, alkylphenyl having 7 to 12 carbon atoms, alkoxyphenyl having 7 to 12 carbon atoms or naphthyl, and X represents the direct bond, alkylene, phenylene or naphthylene.

3. A composition of claim 1 wherein R and R are identical and each represents alkyl having from 1 to 8 carbon atoms, cyclohexyl, benzyl, 3,5-di-tert.-butyl-4- hydroxy-B-phenyl-ethyl, 3 ,5-di-tert.-butyl-4- hydroxyphenyl, phenyl, chlorophenyl, dichlorophenyl,

alkylphenyl having 7 to 12 carbon atoms, alkoxyphenyl having 7 to 12 carbon atoms or naphthyl, and X represents the direct bond, alkylene, phenylene or naphthylene.

4. A composition of claim 1 wherein said higher alkyl esters of thiodipropionic acid are selected from dilaurylthiodipropionate and distearylthiodipropionate.

5. A composition of claim 1 wherein said polyolefin is polypropylene.

6. A composition of claim 4, wherein said sterically hindered phenols are selected from B(3,5-di-t-butyl-4- hydroxyphenyl)-propionic acid octadecyl ester and 3- (3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid tetraester of pentaerythrite.

7. A composition of claim 4 wherein said diacyl hydrazide is CH CONHNHCO(CH2)4CONHNHCOCH 8. A composition of claim 4 wherein said diacyl hydrazide is 9. A composition of claim 4 wherein said diacyl hydrazide is 10. A composition of claim 4 wherein said diacyl hy- 11. A composition of claim 4 wherein said diacyl hydrazide is CfiHsCONHNHCOCONHNHCOCGH5. 

1. A HOMOPOLYMERIC OR COPOLYMERIC POLYOLEFIN COMPOSITION STABILIZED IN THE PRESENCE OF ABSENCE OF COPPER WITH A. 0.01 TO 5% BY WEIGHT OF THE POLYOLEFIN OR A DIACYL HYDRAZIDE HAVING THE FORMULA
 2. A composition of claim 1 wherein -R and R'' are independent of each other and represent alkyl having from 1 to 8 carbon atoms, cyclohexyl, benzyl, 3,5-di-tert.-butyl-4-hydroxy- Beta -phenyl-ethyl, 3,5-di-tert.-butyl-4-hydroxyphenyl, phenyl, chlorophenyl, dichlorophenyl, alkylphenyl having 7 to 12 carbon atoms, alkoxyphenyl having 7 to 12 carbon atoms or naphthyl, and X represents the direct bond, alkylene, phenylene or naphthylene.
 3. A composition of claim 1 wherein R and R'' are identical and each represents alkyl having from 1 to 8 carbon atoms, cyclohexyl, benzyl, 3,5-di-tert.-butyl-4-hydroxy- Beta -phenyl-ethyl, 3,5-di-tert.-butyl-4-hydroxyphenyl, phenyl, chlorophenyl, dichlorophenyl, alkylphenyl having 7 to 12 carbon atoms, alkoxyphenyl having 7 to 12 carbon atoms or naphthyl, and X represents the direct bond, alkylene, phenylene or naphthylene.
 4. A composition of claim 1 wherein said higher alkyl esters of thiodipropionic acid are selected from dilaurylthiodipropionate and distearylthiodipropionate.
 5. A composition of claim 1 wherein said polyolefin is polypropylene.
 6. A composition of claim 4, wherein said sterically hindered phenols are selected from Beta -(3,5-di-t-butyl-4-hydroxyphenyl)-propionic acid octadecyl ester and 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid tetraester of pentaerythrite.
 7. A composition of claim 4 wherein said diacyl hydrazide is CH3CONHNHCO(CH2)4CONHNHCOCH3
 8. A composition of claim 4 wherein said diacyl hydrazide is
 9. A composition of claim 4 wherein said diacyl hydrazide is
 10. A composition of claim 4 wherein said diacyl hydrazide is
 11. A composition of claim 4 wherein said diacyl hydrazide is C6H5CONHNHCOCONHNHCOC6H5. 